Elevator braking system



Marh 23 1926.

' W. S. ATKJNSON ELEVATOR BRAKING SYSTE M Filed Oct. 17, 1924 PatentedMar. 23, 1926.

UNETED S'IATESv PATENT OFFICE.

WILLARD S. ATKINSON, OF ASI-ILAND, NEW' JERSEY, ASSIGNOR TO ATLANTICELEVA- TOR COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OFPENN- SYLVANIA.

ELEVATOR BRAKING SYSTEM.

Application filed October 17, 1924. Serial No. 744,109.

To all whom it may concern:

Be it known that l, \VILLARD S. ATKIN- SON, a citizen of the UnitedStates, residing in Ashland, county of Camden, State of New Jersey, haveinvented certain new and useful lmproven'ients in'lfilevator Brakinglication.

lily invention relates to a system of brak nism changes from maximum tominimum,

or vice versa, and thereby decrease the rate of change of speed.

In accordance with my invention, a plurality of cumulatively actingbrakes are applied or released in succession to effect smooth, gradualor prolonged change of speed either in starting or stopping the elevator or analogous mechanism. accordance with my invention, the severalbrakes are actuated or controlled by solenoids, electro-magnets orequivalent, either energized or deenergized simultaneously but operatingat different rates or energized or deenergized in succession, to effectsetting or litting of the brakes in succession.

Further in accordance with my invention, there is utilized for operatingthe elevator or the like an alternating current motor of a typeeffecting little or no electro-dynainic braking, in association withelectro-magnetic means or equivalent energized or deenergizedsimultaneously but operating at different rates or energized ordeenergized in succession, to effect smooth, gradual or prolonged changein speed at starting or stopping.

My invention resides in the system, mechanism and features hereinafterdescribed and claimed.

For an understanding of my invention and t'or an illustration of some ofthe various forms my apparatus may take, reference is to be had to theaccompanying drawing, in which:

F 1 is an elevational view oi braking mechanism in accordance with myinvention in association with a diagrammatic view of electricalcircuits.

Svsteins of which the followin is a s ec1- Further in Fig. 2 is asection, partlyin elevation, on i the line 22-ot' Fig. 1.

Fig. 3 is an elevational view of a modified form of my mechanism, inassociation with a diagrammatic view of electrical circuits.

Referring to the drawing, D represents the brake drum or equivalent ofan elevator mechanism used in hoisting or r'aisingand lowering freightor passenger elevator cars or other loads. (lo-acting with the member Dare the brake shoes B, B provided with the brake linings aand arespectively, and pivoted respectively at b and b to the arms c. and cpivoted in turn at d and (P, respectively, to" a fixed member 6. andextending through the members 0 and 0 are the adjusting pins or bolts fwhich confine or limit the angular movements of the brake shoes upontheir pivots b.

Carried by the fixed memberc is the up wardly extending arm or bracket 9carrying at its upper end the pivot pin or bolt h and havingthedownwardly extending lug 2'.

Pivoted independently of each other upon the pin it are the lever arms Land L having pivoted thereto the interiorly threaded nuts or pins j, jrespectively, into which are threaded, respectively, the rods 712,70pivoted at the1r outer endsat m, m respectively, to the aforesaid arms 0and 0 provided,

respectively, with the recesses 12, 71 against whose bottoms engage thesprings 0, 0 respectively, whose other ends engage, respectively, thecollars 1), p confined by the nuts or heads q, "9 respectively, upon therods 1, r extending freely through the arms 0, 0 and secured,respectively, at their inner ends to the aforesaid lug 2'. H c

Pivoted to the lever arms L, L at 8, 8

respectively, are the connecting rods t, F,

pivoted at u, a to the cores or armatures C, C of solenoids orelectro-magnets whose energizing windings are indicated at W The springs0 and 0 operate to set the brake shoes B, B against the drum D, and thesolenoids or electro-magnets W, V when energized move the levers Land Lin counterclockwise and clockwise directions, respectively, to actuatethe arms 0, 0 in counterclockwise and clockwise directions,

respectively, about their pivots (Z, (Z to lift the brake shoes B, Bfrom the drum D in opposition to the springs 0,- 0 and upondeenergization of the solenoids the springs set the brake shoes againstthe drum.

Carried by A three phase alternating current supply circuit isrepresented by the conductors 1, 2 and 3 leading to one set of contactsof the switch comprising the movable switch members 1, 5 and 6, of which4 connects with one terminal of the three phase alternating cur rentmotor M, such as an induction motor, or the like. The switch member 5connects with the contacts 7 and 8 and switch member 6 connects withcontacts 9 and 10. Co-- acting with the pair of contacts 7 and 9 are theswitch members 11 and 12, whereby the conductors lt and 13, connectingwith the remaining terminals of the motor M, with the terminals of thewinding N and with the terminals of the winding of the relay R, may bebrought into communication with the line conductors 2 and 3,respectively. Similarly, there co-act with the pair of contacts 8 and 10the switch members 15 and 16 connecting, respectively, with conductor;13 and 14, whereby they may be brought respectively into comn'iunicationwith the aforesaid conductors 2 and Accordingly, the switches 11, 12 and15, 16 constitute reversing switches for reversing the direction ofrotation of the motor M. These switches are never simultaneously closed,but may be operated manually, or electromagnetic-ally under control of aswitch on the elevator car, as well understood in the art, to causeenergization of the motor hi and its rotation in one or the otherdirection.

The windings W and R are energized every time either of the switches 11,12 or 1.5, 16 is closed.

Carried by the arnature or core 1'? of the relay R is the member 18carrying the con tacts 19 and 20, which are adapted to engage and bridgethe stationary relay contacts 21 and 22, upon energization of thewinding R, which causes the upward movement or the member 18 inopposition to the spring 23. The contact 22 is connected to theconductor 13 and contact 21 is connected with one terminal of thewinding W whose other ter minal connects with the conductor 14, wherebywhen the contacts 21 and 22 are bridged by the member 18 the winding Wis energized, drawing its core C downwardly and thereby lifting thebrake shoe B in opposition to spring 0 Attached to the armature or core17 of the relay R is the piston 2 closely fitting and movablelongitudinally in the stationary cylinder 25 and having the restrictedport 26 for retarding movement of the member 18, both upwardly anddownwardly.

When either of the switches 11, 12, or 15, 16 is closed, the windings XVand R- will be energized, causing quite prompt lifting of the brake shoe8 but dela ed rise of the I I I bridging member 18 and therefore delayedenergization oi the winding w and therefore delayed hit-mg of the brakeshoe B Accordingly, the brake shoe B is lifted after the brake shoe 13.Upon opening the switch which caused the energization of the winding VIand relay R the spring 23 will force the member 18 downwardly, but thismotion is again retarded by the dash pot 24, 25, or equivalent retardingmeans, and accordingly the winding \V will be deenergized before thewinding, W and in consequence the brake shoe B, will be set or appliedto the drum 1) in advance of the shoe B The timing effected by the dashpot or equivalent, and by'the length of the contacts .21, 22 may bemade. anything suitable or desirable, but in general, is such that thebrake shoes B and B are either lifted or set several seconds apart, as,for example, two or three seconds apart, or more or less.

Referring to Fig.- 3, one of the electromagnets or solenoids, as 1V isprovided with any suitable means for retarding movement of its core, ascand therefore of the brake shoe B controlled thereby. In the exampleillustrated, the retarding means takes the form of a dash pot comprisinga piston 2 1 secured to the rod t in turn secured to the core C orsecured to the lever L or any suitable element in the train ofmechanism, and the cylinder 25?, the piston being provided with arestricted orifice 26 causing retardation of movement in bothdirections.

In this case both windings W, V are si inultaneously energized anddeenergized upon closure and opening of either of the switches 11, 12 or15, 16.

The operation is similar to that previous ly described in connectionwith Fig. 1, in that the setting and lifting of the brake shoe B? isdelayed with respect to the set ting and lifting of the shoe B.

My invention is of particular advantage when the driving motor, as M, isof the alternating current type, with which regenerative braking,sometimes utilized in connection with direct current motors, is eitherimpossible or unsatisfactory. It will be understood, however, that myinvention is also applicable in case the driving motor is of the directcurrent type, especially when not utilized for regenerative orelectro-dynamic braking, though where regenerative or electro-dynamicbraking is utilized, with either direct or alternating cnrrent motors,my invention may also be used with advantage.

In accoreance with my invention, the acceleration is controlled by themechanical or friction brakes alone or in association with theelectro-dynai'nic or other braking. By my mechanism the acceleration isgradual or prolonged, both when the car or elevator mechanism isstarting and stopping. My mechanism is particularly of advantage for thenegative acceleration or stopping. In stopping, when the motor isdeenergized,

first one brake shoe is applied and some time thereafter the second,with the result that the kinetic energy or momentum of the sys tem isfirst decreased by one brake shoe,

which does not bring the apparatus to rest,-

and later additionally by the second brake shoe which, actingcumulatively with the first applied brake shoe, brings the system ormechanism to rest without shock or suddenness, and assists in causingthe car accurately to register with or find floor levels.

In starting, the acceleration is again graduated or prolonged, first byraising one brake shoe and an appreciable time there-. after the other,with the result that after lifting of the first brake shoe the motor maystart the mechanism, but the motion is resisted by the second brake shoeuntil it is lifted.

In starting a car downwardly,,particularly when loaded, the tendency isimmediately or quickly to attain considerable or high velocity, themotor in such case starting without substantial load upon itself, anditself in no way or but slightly retarding the car and its load. Thismode of op eration is improved, however, in accordance with myinvention, since when the first brake shoe is lifted, the second is notalone able to hold the car and its load against movement, but allowsthebrake drum to slip and to some extent throw a load upon the motor.Upon lifting of the second shoe the speed increases to normal descendingspeed.

What Iclaim is: i

1. The method of controlling the acceleration of elevator mechanismprovided with driving mechanism and-a plurality of brake mechanisms,which comprises operating one of said brake mechanisms'with respect to abrake drum and after a period of time operating another of said brakemechanisms with respect to the same drum to graduate and prolong theacceleration.

2. The method of controlling the negativ acceleration of elevatormechanism provided with driving mechanism and a plurality of brakingmechanisms, which comprises operating one of said brake mechanisms withrespect to a brake drum to apply a braking effect, and after a period oftime operating another of said brake mechanisms with respect to the samedrum to apply a cumulatively acting braking effect to graduate andprolong the acceleration.

3. The method of positively accelerating elevator mechanism providedwith driving mechanism and a plurality of brake mechanisms operatingcumulatively on a brake drum to hold said elevator mechanism at rest,which comprises operating one of said brakemechanisms with respect tosaid drum to reduce the total braking effect, and after a period of'timeoperating another of said brake mechanisms with respect to said drumfurther to reduce the braking effect to prolong the period duringWhichthe total braking effect is reduced- 4. The method of operatingelevator mechanism provided with an electric driving motor and brakemechanisms, which comprises deenergizing the electric motor,

and operating said brake mechanismsat times differing from each otherfor producing a graduated negative acceleration of said elevatormechanism.

5; The method of operating elevator mechanism provided with an'electricdriving motor and brake mechanisms, Which comprises deenergizing theelectric motor and substantially simultaneously operating one of saidbrake mechanisms to produce a brak ing effect, and thereafter operatinganother of said brake mechanisms, to prolong the negative accelerationof said elevator mechanism.

6. The method of operating elevator mechanism provided with an electricdriving motor and brake mechanisms, which comprises energizing theelectric motor, and operating said brake mechanisms at times differingfrom each other for producing a graduated positive acceleration of saidelevator mechanism.

'7. The method of operating elevator mechanism provided with an electricdrivin motor and brake mechanisms, Which comprises energizing theelectric motor and substantially simultaneously -operating one of saidbrake mechanismsto reduce the braking effect upon said'elevatormechanism, and thereafter operating another of said brake 'mechanismsfurther to reduce the braking effect upon said elevator mechanism, topro long the positive acceleration of said elevator mechanism. v

8. The combination with an elevator mechanism,of a brake drum and aplurality of brake mechanisms therefor, and means for operating saidbrake mechanisms with respect to said drum a predetermined inter al oftime apart, to prolong the acceleration of said elevator mechanism.

a sourceof power for driva plurality of brake mechan elevator ing effectof said brake mechanisms upon said elevator mechanism.

1:2. The combination with an elevator mechanism, of a source of powerfor driving the same, a plurality of brake mechanisms, means fordiscontinuing the operation of said elevator mechanism by said-source ofpower, and means for setting said brake mechanisms at different timeswith respect to discontinuation of operation of said elevator mechanismby said source of power for prolonging the negative acceleration of saidelevator mechanism by said brake mechanisms.

18. The combination with an elevator mechanism, of an electric motor fordriving the same, a plurality of brake mechanisms, means for energizingsaid motor, electro magnetic means controlling said brake mechanisms,and means co-operating with said electro-magnetic means for causingcontrol of said brake mechanisms at different times with respect to theenergization of said motor for prolonging the positive acceleration ofsaid elevator mechanism.

14-. The combination with an elevator mechanism, of an electric motorfor driving the same, a plurality of brake mechanisms, means fordeenergizing said motor, electromagnetic means controlling said brakemechanisms, and means co-operating with said electromagnetic means forcausing control of said brake mechanisms at different times with respectto the deenergization of said motor for prolonging the negativeacceleration of said elevator mechanism.

15. The combination with an elevator mechanism, of an electric motor fordriving the same, brake mechanisms, a plurality of electro-magneticdevices each controlling one of said brake mechanisms, switchingmechanism controlling simultaneous energization of said motor and atleast one of said electromagnetic devices, and means for delaying thecontrol of another of said brake mechanisms by its electromagneticdevice, whereby reduction of braking effect upon said elevator mechanismis prolonged.

16. The combination with an eleigator iechanism, of an electric motorfor dr'vin the same, brake mechanisms, a plurality or electro-magneticdevices each controlling one of said brake niechanisn'is, switchingmechanism controlling simultaneous deenergir iation of said motor and atleast one of said electroanagnetic devices, and means for delaying thesetting of another of said brake mechanisms, whereby the negativeacceleration of said elevator mechanism prolonged. 1?. The combinationwith an elevator mechanism, of an electric motor for driving the same,brake mechanisms, an electromagnetic device for controlling each of saidbrake mechanisms, switching mechanism for simultaneously energizing anddeenergizing said motor and said electrormagnetic devices, and meansassociated with one of said brake mechanisms for retarding its movement,whereby the acceleration of said elevator mechanism is prolonged.

18. The combination with an elevator mechanism, of a brake drumtherefor, a plurality of brakes movable independently of each other andco acting with said drum, means biasing each of said brakes towards saiddrum, an electromagnetic device for actuating each of said brakes inopposition to its said biasing means, and means for causing movement ofsaid brakes toward or away from said drum at different times.

19. The combination with an elevator mechanisn'l, of a brake drumtherefor, a plurality of brakes movable independently of each other andcor-acting with said drum, means biasing each of said brakes towardssaid drum, an electro-magnetic device for actuating each of said brakesin opposition to its said biasing means, means for causing simultaneousenergization of said electromagnetic devices, and means for retardingthe movement of one of said brakes by its electro- :iagnetic device.

20. The combination with an elevator mechanism, of a brake drumtherefor, a plurality of brakes movable independently of each other andco-acting with said drum, means biasing each of said brakes towards saiddrum, an electric-magnetic; device for actuating each of said brakes inopposition to its said biasingmeans, means for causing simultaneous.energization of said electromagnetic devices, and means for retardingthe movement of one of said brakes towards said drum u 3011 deenerization of its electro-magnet-ic device.

'21. 'lhe combination with an elevator mechanism, of a brake drumtherefor, a plurality of brakes ce-acting with said drum, concentricallypivoted levers connected, respectively, to saidbrakes, independentlyoperating means for biasing each of said brakes towards said drum, anelectromagnetic device operating upon ,each'of said lovers in oppositionto said biasing means, and means for ensuring the movement of saidbrakes at different times with respect to said drum,

22. Elevator mechanism comprising a brake drum, a plurality of brakesco-acting with said drums, a bracket, a plurality of leversconcentrically pivoted on said bracket, means connecting each of saidlevers with one'of said brakes, rods secured'to said bracket, springabu-tments carried by said rods, springs intervening between saidabutments and said brakes for biasing said brakes towards saiddrum, anelectro-m'agnetic device operating upon each of said levers inopposition to the spring, and means for ensuring movement of said brakesat different times With respect to said drum.-

3. Elevator mechanism comprising a brake drum. a plurality of brakesco-acting with said drum, a bracket, a plurality of leversconcentrically pivoted on said bracket, means connecting each of saidlevers with WILLARD s. ATKINSON.

